1. Field of Invention
The present invention relates to an assembly comprising a pressurized-gas storage tank and a control device for filling and/or tapping-off from said tank.
2. Related Art
The supply of gas to gas-consuming devices, for example fuel cells, presents numerous problems. In particular, it is important to simplify and secure the supply by, in particular, working along the principle of exchanging an empty tank for a full tank.
This problem is all the more sensitive because the current trend is to increase service pressures with a view to offering a better ratio between the mass of stored gas and the overall mass of the tank, combined with smallness of size.
In addition, such systems are becoming more widespread, involving use of the gas by non-specialists (professionals such as nurses, laboratory workers, for example, or by the general public such as DIY enthusiasts, motorists, etc.).
One objective of the systems for storing fluid and of the devices for filling them and/or for tapping fluid off from them, is to make the handling operations needed to exchange an empty tank for a full tank easier. The storage systems have in addition implicitly to provide a level of safety that allows the handling operations to be performed by non-specialists while at the same time improving the safety and productivity in tank processing centers.
It is known practice for gas to be stored in liquid form. In known solutions (CO2 for example), this is performed quite naturally and does not require the use of special facilities. In most cases (for example that of hydrogen), however, it is necessary to maintain temperature conditions such that the use of special facilities is compulsory (thermal insulation, control of boiling or “boil-off”). This operation makes the solution for storing liquid somewhat irrelevant because it is far too complicated and ill suited to the idea of exchanging an empty one for a full one.
Solutions for storing gas in gaseous form conventionally include cylinders equipped with a simple valve which, if open, places the user in direct contact with the storage pressure. It is therefore necessary, in order to use the gas, to connect up equipment (pressure regulators, flow meters, etc.) and this entails tooling and tricky operations. These operations become all the more risky when the user is not a professional (with the risk of leaks, forcible expulsion of parts, etc.).
Lightweight small-sized gas refills are known, these proposing a solution which is to provide the canister with a valve that has no actuating member, but the disadvantage with these is that the gas is delivered at the storage pressure.
In order to guard against the risks associated with the high pressure, canisters or cylinders may be equipped with a regulating valve which, as far as the user is concerned, allows him access only to a reduced pressure. This solution has the disadvantage of creating a protruding part on the cylinder. This protruding part therefore needs to be protected. This protection is generally formed by a bonnet. On the whole, the weight and size are increased and incorporating the cylinder into the application that requires the gas may lack simplicity.
Furthermore, most reserves of gas delivered to customers need to be mobile. In an extreme case, the self-contained gas source may have to be deployed and to accompany the gas-consuming application, for example to supply a fuel cell at an isolated site or to accompany fire fighters attending an emergency.
Each customer or customer family has its own specific requirements that have to be met as best possible. The consequence of this is to make the industrial organization more complicated because it is necessary to manage a wide variety of products (fluid/tank pairing and fluid delivery conditions).
One problem that needs to be solved is, on the one hand, to offer the user and/or the operator means that make it easier for him to transport and to handle a reserve of gas and, on the other hand, to offer the user means that will allow him to customize the design of a reserve of gas in order to meet the requirements of his particular application and to allow the operator flexibility that will allow him to manage the variety of products needed to meet the requirements of his customers.
Of the solutions for storing gas in gaseous form, cylinders equipped with a simple valve are favored by the operators and by industry for questions of managing the population of cylinders. If open, the simple valve places the user directly in contact with the fluid at its storage pressure. It is therefore necessary, in order to use the gas, to connect up hardware (pressure regulator, flow meter, etc.) which demands tooling and tricky operations, accompanied by the risks involved in this type of operation when the user is not a professional. This solution is therefore not favored by the end-user.
Better favored by the end-user is the regulating valve attached to the cylinder delivering the fluid as the pressure needed by the application. However, use of such a regulating valve places significant constraints upon industry particularly in terms of managing the population of cylinders, maintenance, interface with the filling equipment, etc.
In known designs for storing gas under pressure, the valve incorporates a regulating device which is positioned inside the volume of the cylinder (cf. for example EP-A-1316755). These known devices make it possible in part to limit the volume of the valve but require the user to perform numerous handling and coupling operations in order to fill and tap off from the cylinder.
Thus, none of the aforementioned existing solutions simultaneously considers these specific requirements of industry and those of the customer.
It is one object of the present invention to alleviate all or some of the disadvantages recalled hereinabove of the prior art.